The year from 2008 to 2012 is the first commitment period of Kyoto Protocol. Japanese government has planned to do thinning of abandoned artificial forest (3.3M ha) to promote carbon fixation by the forest. Here the changes in the soil respiration rate(SR) and carbon budget of a Cryptomeria stand (a typical plantation of Japanese cedar) was examined and the effect of thinning on SR were also studied. A study site of 25 years stands (811 stands/ha) was set at Mt. Yunodake, Iwaki city, Fukushima pref., Japan. A quadrat with the size of 30mx30m was placed at the south facing slope with the inclination of 20�. A total of 36 sub-quadrats (5mx5m) also placed in the quadrat where ten measurement points of SR were selected considering the micro-topography. It was measured every month by the ACE station (Bioscientific C. LTD). Thinning was done on October 2011 in a half size of the quadrat. SR showed high dependency on soil temperature before thinning period (July 2010 to Sept. 2011) with a positive correlation (R²: 0.892). Annual SR before thinning was 4.64 (C-t/ha/yr). Although only two months data were available the change in SR was not clear after the thinning when compared with non-thinning sub-quadrats. Comparison with similar field experiments at Chamaecyparis (Japanese cypress) and Larix stands was also done.